Field of the Invention
The presently disclosed subject matter is related to a mirror drive device and a driving method of the mirror drive device, and in particular, related to a structure of a micro mirror device that is suitable for an optical deflector that is used for optical scanning, and a driving method of the micro mirror device.
Description of the Related Art
A micro scanner that is manufactured using a micro process technology of silicon (Si) (hereinafter referred to as “micro electro mechanical system (MEMS) scanner”) features a small size and low power consumption, and a wide range of applications from a laser projector to an optical diagnostic scanner such as for optical coherence tomography have been expected.
There are various driving schemes of a MEMS scanner, but a piezoelectric driving scheme using deformation of a piezoelectric body has a high torque density as compared with the other schemes, and obtains a high scan angle with the small size, so that the piezoelectric drive scheme is promising among the various schemes. In particular, in utilization of a laser display, etc. in which a high displacement angle is required, resonance driving is mainly used, and the high torque of the piezoelectric driving scheme is a great advantage for the utilization.
For example, as discussed in Japanese Patent Application Laid-Open No. 2009-002978, in a conventional piezoelectric MEMS scanner, a scheme has mainly been used in which a torsion bar is connected to a coupling section (coupling section) in an actuator having a structure in which two cantilevers are connected, and the respective cantilevers are driven in opposite phases to perform tilting displacement on the torsion bar (see Japanese Patent Application Laid-Open No. 2009-002978; Tani et al., Optical MEMS and Their Applications Conference, 2006. IEEE/LEOS International Conference on, 2006, 25-26; and Matsuo et al., Japanese Journal of Applied Physics, The Japan Society of Applied Physics, 2010, 49, 04DL19).